-31x^2-248x+620=0

Solution for -31x^2-248x+620=0 equation:

-31x^2-248x+620=0

a = -31; b = -248; c = +620;
Δ = b2-4ac
Δ = -2482-4·(-31)·620
Δ = 138384
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{138384}=372$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-248)-372}{2*-31}=\frac{-124}{-62}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-248)+372}{2*-31}=\frac{620}{-62}
=-10
$